1. Field of the Invention
The invention relates to a lighting device for streets, pathways and the like. Without admitting to be prior art, such light devices include a housing positioned at a distance from a surface that is to be illuminated. At least one lighting module is mounted on a support in the housing and may include a number of lamp units of equal light distribution characteristics. Each of the lamp units may have multiple light sources and lenses, which may be individually assigned to and positioned in front of these light sources in the direction of the light emission for generating a predefined light distribution pattern. The light device may include different lighting modules which are at least equipped with lamp units displaying a different light distribution characteristic.
2. Description of Relevant Art
EP 1 916 468 A1 describes a lighting device for streets, pathways and the like, with a housing containing multiple lighting modules for generating a predefined light distribution. The housing of the lighting device is mounted on a curbside pole, allowing a longitudinal section of the street to be illuminated as the object surface. The lighting modules mounted in the housing are of an elongated design and are provided with a support on which lamp units of an identical type of light distribution characteristic are installed in rows. Each lamp unit essentially consists of an LED light source and, positioned in front of it in the direction of the light emission, a lens. The lamp units of the lighting module are shielded by a common, transparent cover plate.
For generating a predefined light distribution of the lighting device, several lighting modules with different types of light sources and/or different light distribution characteristics are employed. A first lighting module includes lamp units with first lenses which in relation to a central plane emit a relatively narrow light cone. A second lighting module includes lamp units with second lenses which in relation to the central axis emit a relatively broad light cone. Third lighting modules include lamp units with third lenses which emit light cones in a dihedral range located between the light cone of the first lamp unit and the second lamp unit. The lighting modules with the lamp units that emit in the dihedral range a relatively narrow light cone are so positioned in the housing that they illuminate a marginal area of the surface to be illuminated. A main area of the surface to be illuminated is illuminated by the lighting modules with the broad-beam lamp units. In relation to the central axis the light cones of the different lighting modules or lamp units are symmetrical. It follows that the lighting device for homogeneously illuminating the street section is relatively complex and expensive. Another drawback is the fact that several differently configured lenses must be used.